When i first got clipless i fell numerous times when i was getting used to them in an empty parking lot, and then only once when i ventured offroad. That last time, i landed on my ass on a sharp protruding root sticking out of the trail.

for some reason, after that, i never forgot to clip out even in the most dire situation!!!

This was all about 11 years ago when i was fourteen. Clipless pedals do quickly become second nature, and you don't even think about them after a while. I can't imagine riding without them now - they are one of the milestone improvements in cycling from the last century, IMO.